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Topic: Fermenting in blue (or red) coolers? (Read 2057 times)

In thinking through my brewing procedures to make them more sustainable in the new place, I've been looking at how best to organize fermentation. What I'm imagining are a few (~3-4) large coleman coolers (the big kind) stacked one on top of the other, each fermenting its own beer, or just holding sanitizer ready to be used later. For temp control, I was thinking to run a small stainless coil in through the drain spigot. Since they're insulated it should be relatively easy to keep them at a reasonable temp. Any downsides to this set up?

Are the linings of these coolers the same food quality plastics as fermenting buckets? If not they may throw off some odd flavors or worse. If they are, i dont see a problem with it. it sounds like a good idea, especially if you have space limits.

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Granite Coast Brewing Company.Building a clone of The Electric Brewery to use as a pilot system for new recipes!

I am a materials engineer who has designed plastics formulations for almost twenty years. I have a BS degree in chemistry and did my MS thesis in the field of polymer science and engineering. I have experience in many different polymer systems (PE, PP, PVC, PUR, PA, EVA, PC, PS, ESBS, PET, EPDM, SBR, CSM, FEP, PTFE, PVDF, ECTFE, just to name a few).

Plastics are generally misunderstood. Plastic compounds are generally composed of the base polymer (i.e. PE, PP, PVC, etc.) and additional additives that further enhance the polymer's physical or chemical properties (i.e. impart flexibility, add flame retardancy, increase impact resistance, etc.). For example, white rigid PVC pipe that we buy in home improvement centers is the same polymer as garden hoses, namely PVC. yet these two items behave very differently in terms of flexibility. This is because an additive called a plasticizer (essentially an organic oil) has been added to the hose to impart flexibility. The plasticizer molecules essentially "fill in" between each of the long chain polymer molecules causing them to slide across each other. Think of a lube on a molecular level. It's important to remember the difference between polymers and compounds. (Note: the lead that is in garden hoses is from a lead salt (lead phthatale or lead sulfate) that is used as a heat stabilizer. It will leach out.)

As far as leaching goes, a food grade polypropylene will not typically contain anything harmful that will leach into the mash at an unacceptable level (true for HDPE as well). The company can not label it as food grade if this was the case (this isn't China where companies can put melamine into dog food without regulation, or lead based paints on toys). The only thing I can think of that might leach into the mash would be a mold release agent that's there to help separate the liner from the mold during it's initial manufacturing process. Probably a food grade mineral oil or paraffinic compound that's easily removed with soap and water. There may also be some type of antioxidant or UV inhibitor to stabilize the polymer from high manufacturing temperatures or sunlight exposure. Again, these would be food grade and not pose a risk at the levels added. Look at some food labels and see how often you find BHT (butylated hydroxytoluene), yet you still eat this. Here's something else to think about: The residual component (terephthalic acid) used to make polyethylene terephthalate (PET) is in every plastic soda bottle because it leaches into the drink, especially the longer a bottle stays on the shelf. This is why a coke tastes different in plastic than glass or a can. Yet PET bottles are food safe.

Warping and cracking of the plastic is most likely due to temperature interactions. This is a physical event, not chemical. It has to do with the crystalinity of the polymer itself. Other things could be that the actual polymer itself could be oxidizing (which is a chemical reaction) over time at high temperatures if NO antioxidant is present. Also consider the melting points of LDPE, HDPE and PP (~100C, 130C and 160C respectively). LDPE softens at about 80C or so and HDPE softens at about 120C or so - meaning that at mashing temperatures, you're probably good with HDPE or PP. One has to remember that if you pour boiling water into a LDPE lined cooler, you could do some damage, but are fine in a HDPE or PP lined cooler.

A cooler fermentor is a great idea. I've been wanting to do a German weiss in a shallow fermentor to see how the flavor profile differs from a typical bucket fermentor. I've got a couple of long rectangular coolers that could work great for this. Only issue is that they won't fit in my fermentation chamber. I'll have to get some stainless steel tubing like you're thinking and give this a try.

I don't think you will be able to seal the cooler and attach an air-lock.

I've done a sour mash in my Gott cooler mash tun, and it didn't have an air-tight seal like buckets normally do. I mashed in and let it set in the basement, and the next morning the entire basement was FUNK-Y.

It is an old cooler (4 years old or so), but I imagine new coolers aren't build to seal that tightly (any cooler will leak if you put it on its side).

How do you plan to set up temp control? Recirc ice water through the stainless coil with a pump actuated by the controller?

I don't think you will be able to seal the cooler and attach an air-lock.

I wouldn't think sealing the cooler is critical. At least not during active fermentation.

I've left carboys open while they are blowing off to no ill effect. Of course I put the airlock back on when they settled down.

For the cooler, I would think it should seal well enough to keep most stuff out even after active fermentation stops. Probably not good for long term aging.

+1

I have a few lids laying around that I never drilled out or installed grommets on. Sometimes they're all I have laying around so I just lay them loosely over the bucket. For 2 weeks or so in primary I've never noticed an issue. For long-term aging I'd definitely want to rack to a carboy, though.

I don't think you will be able to seal the cooler and attach an air-lock.

I wouldn't think sealing the cooler is critical. At least not during active fermentation.

I've left carboys open while they are blowing off to no ill effect. Of course I put the airlock back on when they settled down.

For the cooler, I would think it should seal well enough to keep most stuff out even after active fermentation stops. Probably not good for long term aging.

+1

I have a few lids laying around that I never drilled out or installed grommets on. Sometimes they're all I have laying around so I just lay them loosely over the bucket. For 2 weeks or so in primary I've never noticed an issue. For long-term aging I'd definitely want to rack to a carboy, though.

Agreed - he'll just need a few carboy's/kegs/buckets if making beers that need conditioning time